Automatic choke for internal-combustion engines



EQ, 944. Y L LANGHAAR 2,359,998

AUTOMATIC CHOKE FOR INTERNAL-COMBUSTION ENGINES Filed Jan. 14, 1942 @QM/@Mx Patented Oct. 10, 1944 AUTOMATIC CHOKE FOR INTERNAL- COMBUSTION ENGmES Louis Langhaar, Mount Olive Township, Morris County, N. J.

Application January 14, 1942, Serial No. 426,717

15 Claims.

I'he title of the invention indicates the general character of the device to which it relates and specically the invention relates to thermo-electric controlled automatic chokes for such engines, and an object of the invention, among others, is the provision of a device of this type which will improve performance under varied conditions and which may be produced at a minimum cost, the functions of these chokes being so well understood by those skilled in the art as to need no general description herein for a clear understanding of the operation of the device, its construction being illustrated in the accompanying drawing in which- Figure 1 is a side view of my improved device shown enclosed in a case which is cut in section and with the parts in normal inactive positions.

Figure 2 is a similar view but looking in a direction at right angles to the point of view of Fig. 1.

Figure 3 is a view similar to Fig. 1 but showing the position of the parts on operation of the starting switch to crank the motor.

Figure 4 is a. view similar to Fig. 3 but showing the relative positions of the parts after the engine has been operating for a period.

In the construction of this type of thermoelectrically controlled devices the electro-magnetic unit is the item of material cost, and as an important feature of the invention, among others, resides in production of devices at minimum cost I have partially directed my attention to this feature. By the superior utilization of scientic principles of mechanical design and arrangement of the operating parts I have accomplished a purpose which enables me to use the smaller and cheaper forms of electro-magnetic control. As electro-magnetic force, whether in a solenoid or electro-magnet, decreases inversely as the square of the distance through which it must act any decrease in the needed range of action appreciably reduces the size and costv of the electro-magnetic unit required. A solenoid being appreciably cheaper than an electro-magnet of the same strength of desirable range the construction and arrangement of my improved device permits not only the use of a solenoid but one of the smallest type that is able to operate a choke control, although I do not intend to so limit my invention as to avoid the advantages which I gain by virtue of the superior mechanical design of my improved construction, which enables the use of electroat the present time. I emphasize the matter of cost because devices of this type must either made in quantity production or not at all commercially, and if the article is not competitively saleable it does not exist to the public or for the public good. It is therefore seen that a difference of a fraction of a cent in the production of the devices 'by the millions is an important factor in the matter of cost, and consideration must also be given to fabrication costs and the cheapest processes therefor as well as to scrap loss.

- An understanding of my improved construction will at once demonstrate that these factors of cost are taken care of at substantially the practical minimum. It is a purpose of my invention to provide means for mutually free and independent thermostatic and electro-magnetic control of a choke valve which I accomplish as illustrated and described herein. 'Ihere have heretofore been several constructions of this type of device but in all of which there is some form of interlocking, thermostatic, electro-magnetic control of the choke valve and I avoid such interdependence of these elements for the objects of structural simplicity, lower cost, and particularly with better eciency in operation. Automatic chokes have been commonly known as "fuel hogs although convenient and this interlocking of the electrical and thermostatic functions has been one of the primary causes for such serious fault by reason of mutual interference between the functional control means of both. The more parts the thermostat has to contend with the more sluggish and unreliable it becomes and more liable to stick in service, and it is extremely difficult at best to get fast enough thermostatic response as the engine warms up to prevent over choking with its consequent fuel waste and fouling of the spark plugs and the entire engine.

The functional purpose of the thermostat is served during a relatively early part of the warming up process, for the engine soon reaches an internal temperature permitting best operation without choking, yet the thermostat must be located where heat response is slower than inside the engine cylinder. Then, when the functional thermostatic purpose has been served it is important to prevent undue needless heating of the thermostat with consequent distortion.

I prefer to locate the thermostatic device on or adjacent to the engine exhaust manifold. The manifold may be variously constructed in any desired manner for such heating purposes not necessary to set forth herein. When the thermostat has reached a desired thermal exure use a heat insulating device to block 'o the excessive heat within such limits as desired is employed, and such heat insulating device is also thermostatically controlled. A thermostatically regulated heat control device is not new per se but I employ such device in a new and varied manner and in a dierent combination of parts than heretofore used.

It is functionally immaterial Whether the electro-magnetic means be a solenoid or electro-magnet or whether this device acts by pushing or pulling as these are matters which'may be variously arranged within the skill of an electrician or mechanic to obtain the results desired and without a specific showing as to the various ways in which the desired results may be attained. My improved choke operating device is so constructed and arranged that upon the starting of a cold engine the choke valve is shut substantially tight while the starter is being employed to suck fuel into the engine, but such valve will be opened enough to admit requisite combustion air immediately when the engine begins to fire. The

electro-magnetic unit is connected in conjunction with the engine starter and operates only when the starter is used and functions as just stated.

My improved device is further so constructed and arranged as not to close the choke valve when the engine is hot as obviously this would create trouble and this is an important feature because it corrects and improves operations in this respect over devices heretofore contemplated but not extensively in commercial use at the present time, my use of a thermostat and mechanical means eliminating the function of an electromagnet unit when such is not needed and these being combined in such manner as to overcome objections to means for breaking electric circuits by thermostatic means heretofore contempated .by others. With this arrangement I effect a control of operation of the thermostatic unit to open the .choke after the engine beginsto warm up in a most satisfactory way and with the choke fully open well before the engine parts reach full heat. The thermostat completes its useful function long before the engine parts reach full heat and as the heat of the engine is employed to cause functioning of the thermostat the latter continues to flex long after its useful scope is passed and care must therefore be taken to avoid danger of permanent distortion of the thermostat unit. For example,

the useful temperature range is only from one hundred to two hundred degrees F. while the source of engine heat, as the manifold, may reach almost red heat which at times may be as much as seven hundred to eight hundred degrees higher. While the thermostat does not reach such extreme temperature it may reach a temperature and amount of distortion liable to cause permanent set in the material of which it is composed and definite provision is made in my improved device to provide for such contingency.

For the same reason the insulation of the electro-magnetic coils is liable to damage from extreme heat and good engineering principles limit the heat in such coils to substantially two hundred and fifty degrees F. to avoid breaking down of the insulation. The arrangement and construction of my improved device is such as to protect the coils from such heat injury and at the same time without impeding quick thermostatic response thereby effecting most satisfactory results in the operation of the structure.

My improved device is also constructed to provide for the needed lost motion which should be allowed for the proper functioning of the electromagnetic unlt in the cold condition of the thermostat under extreme cold atmospheric conditions, thereby permitting the choke valve to open wide enough when the engine begins to fire and thereby avoid the Well-known troubles incident to over choking of the engine.

It has heretofore been the practice in devices of this type to provide a fixed heat insulating gasket between the thermostat and the source of heat to act as heat protection both for the thermostat and the electro-magnetic unit. This obviously retards thermostatic action and causes over choking while not being adequate protection for the electro-magnetic device, as if it were proper for the latter then-the thermostat would scarcely function at all. My improved device provides proper disposition of the parts and materials for proper functioning to secure maximum efficient results.

This reduction of expense and saving of material in the construction of my improved device is of primary importance at the present time where such devices are largely employed in the construction not only of commercial vehicles but more so in the construction of vehicles employed for defense purposes as the arrangement will effect an appreciable saving in the amount of copper wire needed and practically doubles the usefulness of any given'amount.

It will now have been recognized that the purpose of this device is to control operation of the choke valve in the carbureter to facilitate in particular starting of an engine under cold conditions, said valve not being shown herein as not necessary to a clear understanding of the invention, the rod connecting the lever of the choke valve and my automatic control only being shown. This control may be located in any convenient position, preferably on the exhaust manifold below the carbureter as most easy to connect. However, any source of engine heat may be employed, as warm air or water introduced in any suitable manner to the case enclosing the device, but in order to avoid excess choking and to effect satisfactory opening of the choke valve before the engine parts have attained full heat I prefer to employ the most direct source of heat, to wit. the exhaust manifold.

As the choke valve should be closed substantially tight while the engine starter is being used under cold conditions but should instantly open a limited amount promptly when the engine begins to fire to allow entrance voi" combustion air. this limited amount may be determined by trial and is subject to variation from atmospheric conditions and temperatures, as the latter may vary to an extent of one hundred and fifty degrees F., according to season and location, it is presumed that such limit should be adjustable at will. After the engine starts the choke should open relatively fast as soon as the engine begins to warm up and the selection of thermostat material will deter- :mine such rate of opening with other things equal and experiment will determine for the best results.

Referring to the accompanying drawing the numeral 8 denotes a case in which my improved device may be enclosed, this case being mounted on the manifold 9 of an engine to which the choke control is applied and from which manifold heat is transferred to the chamber within the case. Within the case 8 I yieldingly support a thermostat 'strip as upon a spring secured to the case. The thermostat strip has a thermostatic acting section I of curved shape at on'e end and terminates at its opposite end in a backturned loop II to the end of which one end of a spring I2 comprising the support for the thermostat strip is secured, the opposite end I3 of said spring being secured to the case as shown in Fig. 1. An actuating lever Il for the choke valve is pivotally carried by the thermostat strip as by means of a U-shaped lever support, the closed end of which is secured to the thermostat strip and the branches I5 of which project toward the top of the case 8 to make contact therewith under certain conditions. Said actuating lever is pivotally attached intermediate its ends to said support, being mounted on a pivot I6 supported at its opposite ends in the branches I5, one end of said lever being pivotally attached to one end oi' a choke lever rod I1 that extends through a wall of the case 8 into the interior thereof. Said rod is attached at its opposite end to the end of a choke lever 35 for operation of a choke valve 36 as shown in Fig. 4 in a manner that will be readily understood. 'I'his rod is formed with adjusting bends I8 intermediate its ends for a purpose to be presently described. The end of the lever opposite its connection to the rod I'I underlies the end of a post I9 projecting from the core 20 of a solenoid 2|. This solenoid comprises the usual case within which the core 20 has a reciprocating sliding movement, the usual winding 22 surrounding the core. A light spring 23 may be employed in a manner common to devices of this type for returning the solenoid core to normal position when the coll is deenergized.

The case 2| has a ilange 24 at its supported end which rests against an insulating piece 25 secured against a wall of the case 8. The post I9 is much reduced in size as compared with the core 20, this small post extending through the insulating piece 25 and the wall of the case in position for contact with the lever I4. A spring 28 attached at one end to the backturned end of the thermostat strip and at its opposite end to the lever IB operates to force the free end of said lever toward the post I9 and specially to maintain contact of the end of said lever with the end of the post I9 when the solenoid is deenergized and thereby open the choke valve when the starter is released. The lever support I5 in addition to such function also acts as a stop for the thermostat strip, always bringing the latter to the same position and therefore requiring minimum motion from the solenoid core and thereby reducing the cost of the solenoid by reason of reduction of power required.

lin order to ensure full closing of the choke valve at the time of starting, the parts are so arranged that there is always a space between the end of the lever I4 and the wall of the case and there is therefore no liability of the choke valve being slightly open by reason of the lever resting against said wall.

When the solenoid is energized the end of the y lever I 4 promptly separates from the thermoavoid vibration. The size of the wire will be such as to provide suflicientA stiffness for the purpose required, but such that it may be readily bent for purposes of adjustment, and trial will determine when the proper length has been obtained to provide for the proper space for operation of the lever I4 to certainly open the choke valve. I believe this feature of adjustment between any given cold position of the thermostat and the choke lever is generically new and hence is an important feature of the invention. The yielding support for the thermostat is of simple construction, the spring I2 being slightly weaker than the thermostat.

The small post I9 extending through the heat insulation 25 aii'ords proper protection for the core and this heat insulation for the electromagnetic device provides an independently heat insulated pole which may be made of low heat conductivity material. Proper protection is therefore provided for the core or activating part of the electromagnet hereinbefore referred to, reducing materially any means for the conduction of heat to said parts. This protection 'of the solenoid from extreme heat enables the coils of Wire to be closely wound without liability of danger from overheating and this enables the maximum amount of force to be obtained by the use of a minimum vamount of wire. This arrangement for the electro-magnetic device enables the employment of what I term remote control as said device may be located at any desired distance from the source of heat and will enable different forms of electro-magnetic devices to be employed as may be desired. As is common a non-magnetic washer 2l may be used between the end of the core 20 and the end of the case 2i.

By remote I refer to immunization of the electro-magnetic device from effects of heat, independent of actual distance.

It is to be noted that for the range of thermostatic action the lever I4 functions as part of the thermostat and for such range it is immaterial whether or not the rod II is operated directly by the thermostat or through the intermediary of the lever I4 which latter merely functions as an accessory for further motion by means of the electro-magnetic device.

In order to obtain quick heat and to further protect the device from the danger of overheating I provide a gasket 28 of heat insulating material suspended from the thermostat as by means of a link 29, this gasket being interposed between the thermostat and the source of heat, as the manifold 9, and occupying the position shown in Fig. 1 when the parts are in their normal positions, and rests upon the manifold when the parts are in position with the motor running and therefore in a hot condition.

In the operation of the device the starter for the motor being operated, the electro-magnetic device or solenoid 2| is energized and the lever i4 is therefore tipped on its pivot to move the choke lever rod I1 and thereby close the choke valve in a manner that will be readily understood. Immediately upon releasing the starter, thereby deenergizing the electro-magnetic device, the lever I4 drops back to the position shown in Fig. l. 'I'his action is aided by the return spring 26. This opens the choke valve suill'- ciently to provide the necessary combustion air and as the engine increases in heat the thermostat will operate to gradually open the choke valve more and more as conditions of satisfactory operation may require. As the engine gradually cools when running ceases the thermostat assuming its cold condition will gradually return the parts to the position shown in Fig. 1.

As the thermostat cools the end part I continues to flex as the part I5 abuts against the top wall and thereby stops the major thermostatic motion. This provides automatic correcvtion for the choke to open under extreme climatic conditions, and yet in the simplest and cheapest manner, The desirable length I0 of the thermostat is experimentally determinate and may be anything from zero up according to the specific arrangement of the various parts.

I do not limit myself to a lever such as Il mounted upon the thermostat, though I consider this the cheapest and best arrangement. The lever may be mounted in various positions to function 'in the manner and for the purpose described and it is not absolutely essential that it should be mounted within the case, my primary purpose being the construction of the fewest and simplest parts at the lowest cost for the best performance.

I consider that my arrangement of a thermostatically operated gasket to regulate heat is of prime importance and may embody means for thermostatically regulating heat for the purpose described. Also, whfile I have one thermostat serving every essential thermostatic function, I cover the same generically.

In accordance with the provisions of the patent statutes I have described the principles of operation of my invention, together with the device which I now consider to represent the best embodiment thereof; but I desire to have it understood that the device shown is only illustrative and that the invention may be carried out by other means and applied to uses other than those above set out.

I claim:

l. An automatic choke control mechanism for an internal combustion engine equipped with an electric starter and a choke valve, said mechanism comprising an electro-magnetic device, a thermostatic device and a choke valve actuating member, an operative connection between said electro-magnetic device and said actuating member for operation of the latter, an operative connection between said thermostatic device and said actuating member for operation of the latter Iin sequence with the operation by said electromagnetic device, a stop to restrict thermostatic closing motion of said valve, and means for regulating atmospheric thermostatic operation of said valve independently of said stop.

2. An automatic choke control mechanism for an internal combustion engine equipped with an electric starter and a choke valve, said mechanism comprising an electro-magnetic device, a thermostatic device positioned to derive heat from the engine and a choke valve actuating member, an operative connection between safid electro-magnetic device and actuating member for operation of the latter by the former, an operative connection between said thermostatic device and actuating member for operation of the latter by the former in sequence with the operation of said electro-magnetic device, and thermostatically controlled means for regulating the degree of engine heat applied to the thermostat.

3. A device for controlling the chokevalve of an internal combustion engine, said device comprising a movable member operatively connected with said choke valve, electro-magnetic means for moving said member in'a direction tending to close said valve, thermostatic means located within the inuence of heat -of said engine and operatively connected with said movable member, and thermostatically regulated means positioned to restrict the amount of heat affecting said thermostatic means.

4L A device for controlling the choke valve of an internal combustion engine, said device comprising a movable member operatively connected with said valve, electro-magnetic means for moving said member in a direction tending to close safld valve, and thermostatic means for influencing the position of said movable member responsive to changes in temperature, said movable member being mounted for uniform unchangeable action at all times within its functional range irrespective of the condition of said thermostatic means for the full operative range of said electro-magnetic means.

5. A device for controlling the choke valve of an internal combustion engine, said device comprising a movable member operatively connected with said valve, electro-magnetic means for moving said member in a direction tending to close said valve, and thermostatic means for influencing the position of said movable member responsive to changes in temperature, said movable member being mounted for uniform unchangeable action at all times within its functional range for the full operative range of said electro-magnetic means.

6. A device for controlling the choke valve of an internal combustion engine, said device comprising a movable member operatively connected with said choke valve, and electro-magnetic means adapted to move said valve toward closure and thermostatic means both operatively connected with said movable member for operating it under electrical and thermal action and operative each independently of the other for full functional range of motion thereof.

7. A device for controlling the choke valve of an internal combustion engine, said device comprising electro-magnetic means adapted to move said valve toward closure and operatively connected with said valve, and thermostatic means operatively connected with said valve for influencing its position responsive to temperature changes, both of said means being arranged for functional independent operation each of the other for their respective useful functional operative range.

8. A device for controlling the choke valve of an internal combustion engine, said device comprising thermostatic means operatively connected with said valve for regulating the position of said valve as influenced by temperature, and electro-magnetic means comprising a movable member operatively connected with said valve and operating to move it toward closure and arranged for individual limit of operative motion independent of disposition of said thermostatic means and to move said valve toward closure only within said range of limitation of operative motion.

9. A device for controlling the choke valve of an internal combustion engine, said device comprising thermostatic means operatively connected with said valve for some limit of range of valve motion in response to changes in temperature, and electro-magnetic means operatively connected with said valve and disposed to positively move said valve toward closure within some limit of range of operative motion, both of said range limits being free relatively to each other and both of said means being adapted to move said valve independent of motion by the other within said respective limits of operative motion.

10. A device for controlling the choke valve of an internal combustion engine, said device comprising thermostatic means operatively connected with said valve for some limit of range of valve motion in response to changes in temperature, and electro-magnetic means operatively connected with said valve and disposed to positively move said valve toward closure within some limit of range of operative motion, both of said range limits being free relatively to act and both of said means being adapted to move said valve independently of motion by the other within said respective limits of operative motion, and

said thermostatic means assuming full and in- 12. A device for controlling' the choke valve of an internal combustion engine, said device comprising a movable member operatively connected with said' valve. electro-magnetic means operatively connected with said member to posi. tively move it in a direction to close said valve and having some limit of functional operation, and thermostatic means operatively connected with said movable nember to adjust its position responsive'to temperature changes and to move said movable member beyond the functional limits of said electro-magnetic means as the valve approaches the open position.

13. A device for regulating the choke Valve of an internal combustion engine, said device comprising thermostatic means operatively connected with said valve for regulation thereof responsive to temperature changes, and electromagnetic means operatively connected With said valve to operate it for starting operations of said engine, said device being adapted to function to remove one of said means completely out of the zone of the other of said means to eifect independent action of both of said means relatively to said valve.

14. A device for regulating the choke Valve of an internal combustion engine, said device comprising thermostatic means operatively connected with said valve for regulation thereof responsive to temperature changes, and electromagnetic means operatively connected with said valve to operate it for starting operations of said engine, said device being adapted to function to remove the thermostatic connection with said valve completely out of the influence of the electro-magnetic means to effect independent action of both of said means.

l5. A device for regulating the choke valve of an internal combustion engine, said device comprising thermostatic means operatively connected with said valve for regulation thereof responsive to temperature changes, electro-magnetic means operatively connected with said valve to operate it for starting operations of said engine, and an operating member connected with said valve and carried by said thermostatic means within the range of operation of said electro-magnetic means for starting operations and removable by said thermostatic means out of the zone of operation of said electro-magnetic means for subsequent operations.-

LOUIS LANGHAAR. 

